Manufacture of steel



Patented June 9, 1925.

UNITED STATES PATENT OFFICE.

cIIAnLns CUMINGS, or canned ILLINOIS, ASSIGNOR 'IO comacIAI. STEEL com- PANY, A CORPORATION or ILLmoIs.

MANUFACTURE or STEEL No Drawing. Continuation of application Serial No. December 23, 1919.

To all whom it may concern: 7

' Be it known that I, CHARIns CUMInos, a subject of Great Britain, and resident,- of Chicago, county of Cook; andflState of Illinois, have invented certain new and useful Improvements in the Manufacture of Steel, of which the following is a specification. 1

This application is filed as a continuation of and a substitute for an application for patent filed by myself March 12, 1919, Serial No. 282,579 for process and method of manufacturing steel, 1

The inventionfrelates to the manufacture of steel and contemplates .a treatment of the molten bath, preferably employed im mediately prior to pouring, which has been found to secure in the completed product marked improved physical properties as compared with steels of like or similar chemical composition heretofore produced. The invention is believed to be applicable to the production of steel and so-called steel alloys of any usual chemical analysis,- and in the practice of the invention no substantial change in the chemical analysis of the product has been found to result from the use of the novelstep or steps of the improved process andno such changeis now believed to occur, atleastso far as the-quar tities of the ingredients usually determined in the analysis of steels or now known to exist in steel, are concerned. The object of, the invention is the provision of the .improved method of manufacturing steel hereinafter described and claimed and the improved product resulting therefrom. I The invention may be practiced when the molten bath has been prepared in the ordinary manner and the desired carbon or carbon and alloy content of the finished-product securedin the usual manner and the steel isotherwise considered ready topour into the ladle or ingot mold. When the bath has reached this condition, if the method of treatment specifically described is to be used, it is desirabletoadd to the metal bath a quantityof ore such as tungsten concentrates or chrome ore, or a mixture of these ores. A desirable mixture of materials for this purpose may consist of equal parts of tungsten concentrates con taining about 45% of tungst-ic acid and 282,579, filed larch 12,1919. This application filed Serial No. v$7,004

chrome orecontaining about 45% of chrome ox1de. ;A suitable amountof this mixture isfound "to be 40 pounds .to the ton of metal. Other metallic ores having like qualities may be substituted for or mixed with those named. 1

'After the addition of the ores as described the-bath is preferably poled and the ebullition is allowed to subside. In the preparation of ,a' bath of from one to five tons in an open hearth-or electric furnace this .will take place in about fifteen minutes.

The method of treatment which is at present preferred, and for which the above step of adding ores isa preparation, is the addltion to the bath of an explo sive mixture, and allowing the mixture to become ignited on or beneath the surface of the molten metal. The explosive mixture may and preferably does comprise anintimate mixture of fuel, either solid, liquid or gaseous, with oxidizing material in solid or liquid form. The oxidizing agent may be a single material-or a combination of materials mixed together. An explosive mixture which is found to give' satisfactory results is composed of two to four pounds of finely pulverized charcoal, about four ounces of powdered potassium chlorate, and about eight ounces of barium dioxide. The quantity of the materials named is sufiicient for one ton of molten metal. r

After the' introduction of the explosive mixture the bath is allowed to stand for about five minutes, in the case of a bath of from one to five tons, to allow the action to subside, when it may be poured into the ladle or mold. Larger baths than those mentioned .will require larger quantities of materials, and it may be desirable to allow longer periods-of time for subsidence of action.

It is exceedingly difiicult to ascertainexactly what occurs in the bath when the materials named are added thereto. The most satisfactory theory yet arrived at in explanation of the results attained is believed to be as follows I The ores are useful only as protective agents to prevent oxidation of the carbon content of the metal and of the metal itself under the sudden and considerable rise in temperature resultingfrom the combust1on of the explosive mixture. This theor derives support from the fact that chemical analysis the completed product shows none, or but a trace of the tungsten or chromium in carbon steel, as distinguished from alloy steel, the amount being in no case sufficient, as is now believed to affect materially the physical characteristics and thus account for the improvement in physical properties secured in the product by the use of the invention.

The utilization of the explosive mixture is at present regarded as a practicable and effective method of producing a violent agitation accompanied by a sudden shock and by a substantial rise in temperature. This action differs in kind from such action as is obtained by poling or blowing, or by the introduction of either fur alone or oxidizing agents alone or even by the introduction of mixed fuel and oxidizing agents gradually. In all of these cases the bath is affected gradually. Even the generation of gases in contact with the bath in all cases of which I am aware previous to my invention has been a gradual action since the gas was only generated as successive molecules came into contact with the bath.

The substantial rise in temperature produced in the bath by the combustion of the explosive mixture is believed to be of importance as rendering the bath more fluid and mobile. Whether the gases produced by the combustion of the explosive mixture so react with the gasses occluded in the molten metal as to modify the results has not yet been determined. It is suggested, however, that the large quantity of gas thus generated or released at the surface of or within thebath serves to sweep out occluded gases and particles of slag which would otherwise remain and that the amount of occluded gas and slag contained in the finished product is thus reduced. The higher tem erature of the bath may also reduce the solu ility of both gaseous and solid or molten materials in the metal and the elimination of these substances is, of course, assisted by the greater fluidity of the bath. Furthermore, it is known that the bubbling of gases through liquids containing finely divided matter in suspension frequently promotes elimination of the suspended matter, and it is suggested that the bubbling of the gaseous products of the combustion of the explosive mixture may have this effect with reference to suspended slag and occluded gases contained in the bath.

In any event the results obtained are at present believed to be due in part to a more complete elimination of impurities, in part to a thorough diffusion of the remaining impurities, of any, throughout the mass, thus making the product denser and more perfectly homogeneous. and in part to the production of a finer grain in the product.

Whatever the explanation of the operation of the invention, tests of" the completed product, as compared with steel of substantially the same chemical ana-lvsis made by processes heretofore known and subjected to the same heat treatment, if any, have shown an increase of tensile strength of from 50% upward, and corresponding improvement in metal by the mechanical or chemical effect or combination thereof, which may be produced by the ignition of a mixture of granulated metallic aluminum and metallic oxides in or on a bath of molten metal or the ignition of such a mixture containing scavenging materials such as alloys of some or all of silicon, manganese, aluminum, titanium ormagnesium. The charge, such as mentioned, does not produce a sufficiently sudden eff'ect to bring about the improvement which applicant has discovered that the shock which may be produced by an explosion does bring about.

While the treatment embodying the invention has been described as carried out when the bath has been prepared in its desired chemical analysis, it may in some cases be found desirable to apply it at other stages of the manufacture and later to add some of the constituents desired to have present in the finished product. This and many other modifications may be made in the carrying out of the process without departing from the spirit of the invention.

I claim as my invention:

1. The process of preparing metal which comprises subjecting a molten'bath of the metal to an agitation in the nature of a sudden shock of sufficient intensity to produce'a substantial improvement in the tensile strength and other physical properties of the finished product.

2. The process of preparing metal which comprises subjecting a molten bath of the metal to a sudden shock accompanied and followed by violent agitation said shock being of sufficient intensity whereby in combination with said agitation to produce a substantial improvement in the tensile strength and other physical properties of the finished product.

3. The process of preparing metal which comprises subjecting a molten bath of the metal to a sudden shock strildng widely and substantially instantaneously through the mass of the bath followed immediately by a violent agitation in the nature of flow of the metal said shock being of sufficient 1ntensity whereby in combination with said 1 comprises subjecting a molten bath of the comprises pr paring a metal to an agitation in the nature of a sudden shock, of sufiicient intensity to produce a substantial improvement in the tensile' strength and other physical properties'of the finished product, said shock accompanied by substantial rise of temperature.

5. The process of preparing metal which comprises subjectinga molten bath of the metal to a sudden shock of sufiicient intensity to produce a substantial improvement in the tensile strength and other physical properties of the finished product, said shock accompanied and followed by violent agitation and substantial rise of temperature. 6. The process of making steel which comprises subjecting a molten ferrous bath to an agitation in the nature of a sudden shock of suflicient i'ntensity to produce a substantial improvement. in the tensile strength and other physical properties of the finished product.

7. The process of' making .steel which comprises subjecting a molten, ferrous bath to an agitation in the natureof a" sudden shock of sufficient intensity to produce a substantial improvement in the tensile strength and other physical properties of the finished product, said shock accompanied by a violent agitation;

8. The process of making steel which comprises subjecting a molten ferrous bath to a sudden shock of suflicient intensity to pro duce a substantial improvement in the tensile strength and other physical properties of the finished product, said shock accom- 'panied andfollowed by a violent agitation and substantial rise in temperature.

9. The pr ess' of making "steel which bath of metal ofsubstantially the composition desired in the finished produ'ctand subjecting the bath to an agitation in the nature of a sudden shock.

10. In the preparation of steel the process which comprises preparing a bath of molten,

metal and adding to said bath a single integral mass of material of such a nature and in such a quantity as umes of gas substantially instantaneously whereby to subject the bath to a sudden shock of sufficient intensity to produce a substantial improvement in the tensile strength and other physical properties of the finished product.

11. The process of making steel which comprises preparing a bath 'of molten metal of substantially the analysis desired in the finished product, and adding to said bath a carbon conte of an intimate to generate large vol-f .large quantities of gas substantially instantaneously. I

12. The process of making steel which comprises preparing a bath of molten metal of substantially the analysis desired in the finished product, adding to said bath a quantity-of non-ferrouslore, allowing ebullition to subside, and subjecting the bath to the action of an-agitation in the nature of a sudden shock accompanied and followed bya substantial rise intemperature.

13; The process of making steel which comprises preparing a moltenv ferrous bath and adding to said bath a single integral mass of an'in'timate mixture of fuel and an oxidizing agent in such a quantity as to substantially instantaneously generate large volumes of gas.

14. The process of making. steel which comprises preparing a molten ferrous bath and adding, to said bath a single integral mass of an intimate mixture of finely 'divided fuel in solid form and an oxidizing agent in such a quantity as to substantially instantaneously generate large volumes of 15. The process of making steel which comprises adding to a molten ferrous bath of metal of substantially the analysis desired in the finished product a single inte gral -mass of an intimate mixture of fuel and anoxidizing agent in such a quantity as to substantially instantaneously generate large volumes of gas.

16. The process of 'making steel which comprises adding to a molten bath of metal, of substantially the analysis desired in the finished product, a quantity of non-ferrous ore, allowing ebullition to subside and thereafteradding a quantity of an intimate mixture of a fuel and an-oxidizing agent.

17. The process of making steel which comprises adding to a molten bath of metal, of substantially the analysis desired in the finished product, a quantity of material adapted to p event substantial change of t during subsequent treatment, and a din to the bath a quantity mixture of fuel and an oxidizing agent.-

18. ThBfPI'OCGSS of making steel which comprises adding to a bath of molten metal,

. fuel and an oxidizing agent.

19. The process of making steel which comprises adding to a bath of molten metal, of substantially the analysis desired in the ture of equal parts of tungsten and chrofinished product, a-quantity of a mixmium ores, poling the mass, allowing the ebullition to subside, and adding to the bath a quantity of an intimate mixture of fuel and an oxidizing agent.

20. The process of making steel which comprises adding to a bath of molten metal, of substantially the analysis desired in the finished product, a quantity of ,material adapted to prevent substantial change in carbon content of the bath during subse-' quent treatment, and adding a quantity of an intimate mixture of finely divided fuel and potassium chlorate.

21. The process of making steel which comprises adding to a bath of molten metal, of substantially the analysis desired in the finished product, a quantity of material adapted to prevent substantial change in carbon content of the bath during subsequent treatment, and adding a quantity of an intimate mixture of finely divided fuel, potassium chlorate and barium dioxide.

22'. The process of making steel which comprises adding to a bath of molten metal, of substantially the analysis desired in the finished product, a quantity of material adapted to prevent substantial change in carbon content of the bath d'uring subsequent treatment, and thereafter adding a quantity of an intimate mixture of finely divided fuel in solid form and potassium chlorate.

23. The process of making steel which comprises adding to a molten bath of metal of substantially the composition desired in the finished product a uantity of material adapted to prevent su stantial change in composition during subsequent treatment,

adding to the thus treated bath an intimate mixture of finely siuin chlorate. 1

24. Process of refining molten metal consisting in adding an explosive agent acting divided carbon and potasto mechanically expel gases and impurities,

Whereb to substantially improve the tensile strengt and other physical properties of the finished" product.

.25. Process of treating molten metal consisting in addingaiscavenging charge and an. explosive a enl?-. aeting to mechanically expel gases an impurities whereby to substantially improvethe tensile strength and other physical properties of :the finished product.

26. The process of making steel which com rises preparing a molten bath of the steel of substantially the carbon content de ment in the tensile stren th and other physical properties of the ished product without effecting the carbon content of the bath, and then pouring the metal after completion of the explosive reaction.

27. The process of making steel which comprises preparin a molten bath of the metal having a carbon content desired for the finished product, adding to the bath material to prevent a reduction of the carbon content by the subsequent treatment, adding an explosive agent to the bath to produce a shock therein of suficient intensity to improve the tensile strength and other physical properties of the finished product without effecting the 'desired analysis, and then pouring-the metal after completion of the explosive reaction.

28. The process of makin steel which comprises preparing a molten%)ath of metal, holdin the bath in such a manner that it may yield freely to pressure and subjecting the bath to a shock of explosive violence of'suficient intensity to pro uce substantial improvement in the tensile strength and other physical properties of the finished product.

29. The process of making steel which comprises preparing a molten bath of metal having the carbon content desired in the finished product, adding a charge of scavenging material to the bath, allowing ebullition to subside, holding the 'bath in such a manner as to be free to yield to ressure and subjecting the bath to a shoc of explosive violence of suficient intensity to produce substantialimprovement in. the ten sile strength and other physical properties of the finished product.

30. The process of making steel which comprises preparing a molten bath of metal" having the carbon content desired in the finished product, adding a charge of nonferrous ore, allowing the ebullition to subside and drawin the slag from the surface, holding the bat in such a manner as to be free to yield to pressure and subjecting the bath to a shock of explosive violence of suificient intensity to produce substantial improvement in the tensile strength and other physical properties of the finished produc CHARLES CUMINGS. 

